How is the formula for calculating solar pressure derived?

Thread starter IcedB
Start date Oct 20, 2004
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Pressure Solar

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The formula for calculating solar pressure, F = 2(P x A)/c, is derived from the relationship between momentum flux and energy flux of radiation. It indicates that the force exerted by solar radiation on a surface is proportional to the power and area, adjusted by the speed of light. The discussion highlights that the factor of two accounts for the reflection of photons, effectively doubling the momentum transfer. Additionally, it emphasizes that energy flux can be equated to momentum flux divided by the speed of light. Understanding this derivation is crucial for applications in solar energy and spacecraft propulsion.

Oct 20, 2004

IcedB

Can anyone explain how the following formula is derived:
Force (F) = 2(P x A)/c
P=power A= Area

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Oct 20, 2004

Tide

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Homework Helper

It would appear that's just twice the momentum flux of radiation reflecting off of some area:

2 n \frac {h \nu}{c} A = 2 \frac {P A}{c}

where n is the photon density. In other words, energy flux is the same as momentum flux divided by c.

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